I'm experiencing trouble exporting files from Lightroom then editing them with CS2 then saving them as jpeg. Even if the initial export from lightroom 2 was jpeg! This is apparently a documented bug fixed in CS3 and CSS4 but not in CS2. The solution provided here: http://www.flickr.com/groups/adobe_lightroom/discuss/72157607023379578/ works. Is there a way to script this modification?
I think that a better fix would be to update the camera raw plugin being used by CS2. At least I can save an image exported from LR2 that has adjustment brush adjustments as jpeg with CS2 on my system with ACR 3.7